#include <bits/stdc++.h>
using namespace std;
int main() {
    double x1, y1;
    double x2, y2;
    double x3, y3;
    cin >> x1 >> y1 >> x2 >> y2 >> x3 >> y3;
    double ans = 0;
    ans = sqrt(pow(x1-x2, 2) + pow(y2-y1, 2)) +
          sqrt(pow(x1-x3, 2) + pow(y1-y3, 2)) +
          sqrt(pow(x2-x3, 2) + pow(y2-y3, 2));
    printf("%.2lf\n", ans);
    return 0;
}